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A continental scale daily gridded precipitation dataset for Asia based on a dense network of rain gauges—APHRODITE project

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Monday, 24 January 2011
A continental scale daily gridded precipitation dataset for Asia based on a dense network of rain gauges—APHRODITE project
Washington State Convention Center
Atsushi Hamada, Research Institute for Humanity and Nature, Kyoto, Japan; and K. Kamiguchi, O. Arakawa, N. Yasutomi, and A. Yatagai

An updated version of long-term daily gridded precipitation dataset created by the activities of the Asian Precipitation -- Highly Resolved Observational Data Integration Towards the Evaluation of Water Resources (APHRODITE) project is described. The previous version (APHRO_V0902; Yatagai et al., 2009, SOLA) has already been released for 1961-2004. The current version (APHRO_V1003) is extended for 1951-2007 (additional 13 years from APHRO_V0902) and will be provided on our website (http://www.chikyu.ac.jp/precip/).

APHRO_V1003 is the only product with long-term (57-yr), high-resolution (0.25 and 0.5 degree), and continental-scale based on a dense network of daily rain gauge data for Asia. The number of valid rain gauges used for analysis was between 5000 and 12,000, representing 2.3 to 4.5 times the data available through the Global Telecommunication System network, which were used for most daily grid precipitation products. APHRO_V1003 well reproduces precipitation characteristics in mountainous areas, especially in the Himalayas and the Middle East.

Compared with the previous version more extensive quality controls (QC) are performed before carrying out interpolation. Many kind of errors are found in not only station metainfomation, but precipitation data themselves, e.g., unit-of-measurement error. We will feed the information on erroneous data detected by the QC scheme back to data centers and/or the organizations that kindly provided the rain gauge data. We also develop a new interpolation method based on an Angular-Distance-Weighting (ADW) method. This new method considers local topographical features between rain gauge and interpolation point, e.g., high crest, and reduces the oversmoothing problem in ADW method.

The APHRODITE products have already contributed to studies such as the evaluation of Asian water resources, diagnosis of climate change, statistical downscaling, and verification of numerical model simulation and satellite-based high-resolution precipitation estimates.

In order to apply the APHRODITE precipitation dataset for assessing the impact of climate changes on local hydrological resources, we are making efforts to create daily gridded temperature dataset over the same domain as the precipitation dataset. The status will be shown in the presentation.